Co-molded fastening devices

ABSTRACT

Co-molded fastening devices are provided, including a rigid body and, co-molded with and extending from a portion of the body, a resilient element constructed to provide a user of the device with an improved grip on the device or improved comfort.

TECHNICAL FIELD

[0001] This invention relates to co-molded fastening devices, and more particularly to plastic buckles such as quick release buckles and cord-locks

BACKGROUND

[0002] Many types of fastening devices are formed of molded plastic. Examples of molded fastening devices include quick release buckles, cord-locks, D-ring buckles, loop buckles, triangular buckles, snap hooks, press buckles, slide buckles and step lock buckles, and shoulder pads. Such fastening devices are generally molded from a smooth, rigid plastic such as polyethylene, acetal or nylon.

[0003] In applications such as backpacks and luggage, quick release buckles are used to fasten webbing straps together. Such buckles are easily and quickly fastened and unfastened and, in some cases, provide adjustability of the length of one or both of the straps. In a backpack the quick release buckles are used, for example, to fasten the belt of the pack around the wearer's waist, to fasten a sternum strap around the wearer's chest and, in some cases, to provide releasable, adjustable length compression straps along the sides of the pack. In luggage the buckles are used, e.g., to releasably secure a removable shoulder strap to a gym bag, duffle bag or briefcase. In some applications the buckle may come into direct contact with the user's skin, for example when the buckle is used to secure the chin strap of a bike helmet.

[0004] Lengths of cord or drawstring are often adjustably secured with a cord-lock. Cord-lock devices provide a convenient way to secure and adjust cord, but may be difficult for some users to manipulate with finger pressure, due to their small size.

SUMMARY

[0005] The inventor has found that the functionality, comfort and aesthetic qualities of fastening devices, such as those described above, can be significantly improved by co-molding these devices to include a relatively rigid base and one or more resilient portions. The resilient portions of the fastening device provide a gripping surface that is easier to grasp and manipulate than a smooth, rigid plastic surface. This allows small, difficult to grasp devices such as cord-locks to be more easily operated. Moreover, the resilient portions may provide improved user comfort, particularly when the device contacts a wearer's skin during use, for example when the device is a quick release buckle for the chin strap of a bicycle helmet, or a sternum strap for a backpack.

[0006] In one aspect, the invention features a co-molded fastening device including a rigid body and, co-molded with and extending from a portion of the body, a resilient element constructed to provide a user of the device with an improved grip on the device or improved comfort.

[0007] Implementations of the invention may include one or more of the following features. The fastening device includes a quick release buckle, e.g., a side release buckle, or a cord lock. The fastening device is selected from the group consisting of D-ring buckles, loop buckles, triangular buckles, snap hooks, press buckles, slide buckles and step lock buckles, and shoulder pads. The resilient element has a hardness of from about 20 to 100 Shore A. The quick release buckle includes a male buckle element and a female buckle element constructed for releasable engagement with the male buckle element, and the resilient element is positioned on the female buckle element. The resilient element is positioned so as to prevent a user's skin from being pinched between the male and female buckle elements when they are engaged with each other. The body includes a rigid plastic having a hardness of from about 40 to 90 Shore D.

[0008] In another aspect, the invention features a method of manufacturing a co-molded fastening device having a body and a resilient element extending from a surface of the body, including (a) introducing a first resin into a first mold cavity of an injection mold with moving plates that are movable between a first position, in which the plates define the first mold cavity, and a second position, in which the plates define a second mold cavity adjacent the first, (b) moving the plates to the second position, and (c) injecting a second resin into the second mold cavity.

[0009] The term “fastening device”, as used herein, includes not only devices that fasten components together, but also other types of molded hardware that are constructed to receive webbing or cord for other purposes such as adjustment, securement and cushioning, e.g., slide buckles and shoulder pads.

[0010] Other features and advantages of the invention will be apparent from the description and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

[0011]FIG. 1 is a perspective view of a quick release buckle according to one aspect of the invention.

[0012]FIG. 1A is a front plan view of the quick release buckle of FIG. 1.

[0013]FIG. 1B is a schematic rear plan view of the female buckle element of the quick release buckle of FIG. 1.

[0014]FIG. 1C is a schematic side view of the female buckle element.

[0015]FIG. 1D is a perspective view of a female buckle element according to an alternate embodiment of the invention.

[0016]FIG. 2 is a perspective view of a cord-lock according to one aspect of the invention.

[0017]FIGS. 2A and 2B are, respectively, front and end plan views of the cord-lock of FIG. 2.

[0018]FIG. 3 is a top view of a shoulder pad.

[0019]FIG. 4 is a side view of a snap hook according to one embodiment of the invention.

[0020]FIGS. 5 and 5A are front and side views of a snap hook according to another embodiment of the invention.

[0021]FIG. 6 is a front planar view of a triangular buckle.

[0022]FIG. 7 is a front planar view of a rectangular loop buckle.

[0023]FIG. 8 is a front planar view of a slid e buckle.

[0024]FIG. 9 is a front planar view of a step lock buckle.

[0025]FIG. 10 is a top view of a press buckle.

[0026]FIG. 11 is a front planar view of a D-ring buckle.

DETAILED DESCRIPTION

[0027] Referring to FIGS. 1 and 1A, a quick release buckle 10 includes a pair of engageable male and female buckle elements 12 and 14. Male buckle element 12 includes a pair of prongs 16 that releasably engage side-release openings 18 of female buckle element 14, as is well known in the quick release buckle art.

[0028] The female buckle element 14 includes a resilient portion 20 that is formed of a relatively soft, resilient material. A similar resilient portion 21 is provided on the reverse side of the female buckle element, as shown in FIGS. 1B-1C. A flap 19 of the resilient portion 21 extends beyond edge 23 of the female buckle element, to prevent a user's skin from being pinched between the male and female buckle elements when they are snapped together. This feature is particularly useful when the buckle is used to secure a chin strap, e.g., of a bicycle helmet. The remainder of the quick release buckle is formed of a rigid or semi-rigid base material having a relatively smooth surface. In an alternate embodiment, shown in FIG. 1D, the resilient portion 21 includes side regions 25 that extend beyond the side-release openings 18 to protect the user from pinching in these areas.

[0029] Resilient portions 20 and 21 provide the quick release buckle with improved tactile qualities, making it easier to grasp securely, and thus facilitating cooperative engagement of the two buckle elements by a user. Moreover, the resilient portions 20, 21 provide a relatively soft surface, thereby improving user comfort if the quick release buckle is used in an application in which it will contact the user's skin during use, e.g., as the buckle on a chin strap of a helmet. The resilient portion preferably has a thickness of from about 0.5 to 2.5 mm.

[0030] Referring to FIGS. 2-2B, cord-lock 40 includes male and female cylindrical members 42, 44 having corresponding apertures 46, 48 which can be moved into alignment to define a bore for receiving a cord. The apertures are biased out of alignment, as shown, by a spring 50. The apertures are moved into alignment by pressing end surfaces 52, 54 towards each other (arrows A, FIG. 2A) to overcome the biasing force of the spring. When the apertures are aligned, one or more ends of a cord may be threaded through the resulting bore. The length of the cord on either side of the cord-lock can be adjusted by again pressing surfaces 52, 54 together to release the hold of the cord-lock on the cord.

[0031] The end surfaces 52, 54 are cushioned by resilient portions 56, 58. The resilient portions provide the user with an improved grip on the cord-lock, making it easier to initially grasp and orient the cord-lock, and to keep a secure grip on the cord-lock during operation. The resilient portions also improve user comfort when pressure is applied to the end surfaces. Preferably, the resilient portions each have a thickness of from about 0.5 to 2.5 mm. It is also preferred that the resilient portions have a beveled edge 60, as shown, to provide a smooth contour and further enhance user comfort.

[0032] Suitable materials for the base of the fastening device include rigid and semi-rigid moldable plastics such as polyacetals, acrylonitrile butadiene styrene (ABS), polyamides such as NYLON 6/6, and polyolefins such as polyethylene and polypropylene. Preferably, the base material has a hardness of at least 40 Shore D, more preferably from about 40 to 90 Shore D.

[0033] Suitable materials for the resilient portions of the fastening device include thermoplastic elastomers (TPEs). Suitable TPEs include thermoplastic vulcanates (rubber polyolefin blends), polyetheramides, polyesters, styrene-ethylene-butylene-styrene (SEBS) block copolymers, styrene-butadiene-styrene (SBS) block copolymers, partially or fully hydrogenated styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene (SIS) block copolymers, partially or fully hydrogenated styrene-isoprene-styrene block copolymers, polyurethanes, polyolefm elastomers, polyolefin plastomers, styrenic based polyolefin elastomers, compatible mixtures thereof, and similar thermoplastic elastomers. SEBS, SBS and SIS block copolymers are commercially available from Shell under the tradename KRATON rubber. Other suitable resilient materials include resilient urethanes, silicones and foams. Suitable foams include polyurethane foams, e.g., those prepared from compositions having two components: a foamable, curable polyurethane prepolymer, and an aqueous phase containing a latex and a surfactant. The resilient material may include additives, such as plasticizers, fillers or pigments. The additive may be selected to provide the resilient material with a desired surface texture.

[0034] Preferred resilient materials are durable enough to withstand use during the lifetime of the fastening device without tearing or abrading, and hard enough to provide a secure-feeling grip, while also being sufficiently soft to provide a comfortable degree of cushioning and good tactile properties during use. Preferred materials have a hardness of less than about 100 Shore A, more preferably from about 20 to 100 Shore A.

[0035] The base material and resilient material can be co-molded using conventional co-molding techniques. For example, an injection mold with moving plates may be used, in which case one of the materials is introduced into the mold cavity with the plates in a first position, and the plates are then moved to a second position prior to introduction of the other material. This type of injection molding equipment is well known in the molding field, and utilizes two separate melt barrels to facilitate two different materials being melted into a single mold.

[0036] Examples of other types of molded fastening devices that benefit from the inclusion of resilient elements are shown in FIGS. 3-11.

[0037]FIG. 3 shows a shoulder pad 70, e.g., for receiving the webbing strap of a duffle bag (not shown). The side edges 72 of the shoulder pad include resilient portions 120, to prevent the shoulder pad from cutting into a user's shoulder. The resilient portions improve comfort in the shoulder area by softening side edges 72 to reduce the tendency of the side edges to dig into the shoulder if the webbing strap is rotated or twisted. The shoulder pad may also include a resilient portion on its back surface (not shown), to provide further cushioning. It a resilient portion is provided on the back surface it may be coextensive with resilient portions 120 or separate therefrom.

[0038]FIG. 4 shows a snap hook 80 according to one embodiment of the invention, and FIGS. 5 and 5A show a snap hook 80′ according to another embodiment of the invention. Snap hook 80 is relatively small, e.g., for use as a glove hook for engagement with a small D-ring on a corresponding glove. The resilient areas 120 improve the user's grip on the snap hook when engaging it with a D-ring or other element, and improves comfort in applications in which the snap hook contacts a user's skin.

[0039]FIG. 6 shows a triangular buckle 85, and FIG. 7 shows a rectangular loop buckle 90. FIG. 8 shows a slide buckle 95. FIG. 9 shows a step lock buckle 125. FIG. 10 shows a press buckle 130. FIG. 11 shows a D-ring buckle 135. Each of these devices includes a rigid body 100 and one or more resilient portions 120 mounted on the body. In each of these devices, resilient portions 120 are positioned to provide a user with a more secure grip on the device, to improve the aesthetic appeal of the device, and/or to improve comfort if the device is used in an application where it will contact a user's skin. In some cases, the resilient portions 120 may serve to reduce abrasion of a material that the device will rub against when in use, and/or provide a more secure grip for cinching straps or webbing that pass through the device. In the case of D-ring buckle 135, the resilient areas could be used to prevent or reduce movement of a snap hook around the buckle once the snap hook and buckle are engaged.

[0040] Other embodiments are within the scope of the following claims. For example, other types of fastening devices can be co-molded as described above. Moreover, the resilient portions may be provided on other areas of the fastening devices, depending upon the function or aesthetic qualities that are desired for a particular application. Where more than one resilient portion is provided on a device, the resilient portions may have different colors, surface textures and/or hardnesses. Similarly, the resilient element may be of a color different from that of the body of the fastening device. The resilient element may have any desired shape, including that of a letter, logo or design. 

What is claimed is:
 1. A co-molded fastening device comprising a rigid body and, co-molded with and extending from a portion of the body, a resilient element constructed to provide a user of the device with an improved grip on the device or improved comfort.
 2. The co-molded fastening device of claim 1 wherein the fastening device comprises a quick release buckle.
 3. The co-molded fastening device of claim 2 wherein the quick release buckle comprises a side release buckle.
 4. The co-molded fastening device of claim 1 wherein the fastening device comprises a cord lock.
 5. The co-molded fastening device of claim 1 wherein the fastening device is selected from the group consisting of D-ring buckles, loop buckles, triangular buckles, snap hooks, press buckles, slide buckles and step lock buckles, and shoulder pads.
 6. The co-molded fastening device of claim 1 wherein said resilient element has a hardness of from about 20 to 100 Shore A.
 7. The co-molded fastening device of claim 2 wherein said quick release buckle comprises a male buckle element and a female buckle element constructed for releasable engagement with the male buckle element, and the resilient element is positioned on the female buckle element.
 8. The co-molded fastening device of claim 7 wherein the resilient element is positioned so as to prevent a user's skin from being pinched between the male and female buckle elements when they are engaged with each other.
 9. The co-molded fastening device of claim 1 wherein the body comprises a rigid plastic having a hardness of from about 40 to 90 Shore D.
 10. A method of manufacturing a co-molded fastening device having a body and a resilient element extending from a surface of the body, comprising introducing a first resin into a first mold cavity of an injection mold with moving plates that are movable between a first position, in which the plates define the first mold cavity, and a second position, in which the plates define a second mold cavity adjacent the first, moving the plates to the second position, and injecting a second resin into the second mold cavity. 